Inorganic Astatine Chemistry: Formation of Complexes of Astatine

VlSSER, Gerard W. M.; Diemer, Eduard L.

doi:10.1524/ract.1983.33.23.145

Cited by 35 publications

(15 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such a diatomic species is, however, unlikely to exist considering the range of astatine concentrations studied. 41 Furthermore, our investigations using quantum chemistry methods show that the expected standard potential of the At 2 /At -couple, about 0.18 V vs NHE, could not correspond to the measured redox potential, 0.36 ( 0.01 V. Hence, the exchange of two electrons rather shows the formation of At(I). Its presence as the cationic species At + will notably explain the ability of the species to react with halogen anions to form AtX m n-species.…”

Section: Discussionmentioning

confidence: 70%

See 1 more Smart Citation

Astatine Standard Redox Potentials and Speciation in Acidic Medium

et al. 2009

View full text Add to dashboard Cite

A combined experimental and theoretical approach is used to define astatine (At) speciation in acidic aqueous solution and to answer the two main questions raised from literature data: does At(0) exist in aqueous solution and what is the chemical form of At(+III), if it exists. The experimental approach considers that a given species is characterized by its distribution coefficient (D) experimentally determined in a biphasic system. The change in speciation arising from a change in experimental conditions is observed by a change in D value. The theoretical approach involves quasi-relativistic quantum chemistry calculations. The results show that At at the oxidation state 0 cannot exist in aqueous solution. The three oxidation states present in the range of water stability are At(-I), At(+I), and At(+III) and exist as At(-), At(+), and AtO(+), respectively, in the 1-2 pH range. The standard redox potentials of the At(+)/At(-) and AtO(+)/At(+) couples have been determined, the respective values being 0.36 +/- 0.01 and 0.74 +/- 0.01 V vs NHE.

show abstract

Section: Discussionmentioning

confidence: 70%

“…The standard potential extrapolated at pH ) 0 is 0.74 ( 0.01 V. This value appears coherent with those published in the literature. 3,41 …”

Section: (A) Species I/species IImentioning

confidence: 99%

Astatine Standard Redox Potentials and Speciation in Acidic Medium

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The chemical form of this species remains a subject of discussion [18]: whereas Visser et al described the extraction of astatine from nitric acid into DIPE by an interaction of the neutral complex AtO(NO 3 ) with the organic solvent [15], a similar extraction mechanism was proposed by Yordanov et al [12] by considering the extraction of the complex AtO 2 (NO 3 ) with astatine present at the oxidation state +V. In this study, considering the discrepancies reported in the literature, astatine is represented by the At(x) + species.…”

Section: General Considerations On Astatine Extractionmentioning

confidence: 99%

“…A simple kit for wet recovery of astatine-211 has been proposed [12]. The principle is to use the ability of astatine to be efficiently extracted in the organic solvents (dibutylether, carbon disulfide, benzene, methyl-isobutyl-ketone) from acid solutions (nitric acid, perchloric acid, acetic acid) [12][13][14][15]. The mechanisms of these solvent extractions and the chemical nature of astatine species involved in this process remain uncertain.…”

Section: Introductionmentioning

confidence: 99%

Extraction of astatine-211 in diisopropylether (DIPE)

et al. 2009

View full text Add to dashboard Cite

The extraction mechanism of astatine-211 in diisopropylether (DIPE) is studied by analyzing the effect of the nature of the aqueous solution and organic solvent on the distribution coefficients characterizing the ratio of organic and aqueous concentration of astatine (D). On the one hand, at a given pH value, D was shown to be independant of the nature and concentration of the counter-ion present in the aqueous solution (Cl-, ClO4-, NO3-). On the other hand, the nature of the organic solvent had a strong effect. D increases as the polarity of the organic solvent increases. These experimental observations are explained by the solvation of astatine by the organic solvent. The back-extraction of astatine from the organic to the aqueous phase is efficient in basic conditions. This is explained by the formation of a hydrolyzed species of astatine presenting no affinity for DIPE. Hydrolysis constants of astatine are deduced from experimental data (logβ1=-3.0±0.1 and logβ2=-14.2±0.1)

show abstract

“…These forms of astatine were determined at low concentration with chemistry techniques that can be used at a tracer level such as co-precipitation, liquid extraction, or electromigration experiments, with the knowledge of iodine chemistry as a guide. Most of the descriptions of the oxidation states presented below rely on works by Johnson et al, 19 Appelman, 20 Visser and Diemer, 21,22 and Dreyer et al [23][24][25] Also, more exhaustive information can be found in the DOESponsored Nuclear Science Series monogram by Ruth et al 26 At(-I). The (-I) oxidation state is probably the most clearly established form of astatine with a strong similarity with iodide.…”

Section: Inorganic Chemistry Of Astatinementioning

confidence: 99%

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Guérard

Gestin

Brechbiel

2013

Cancer Biotherapy and Radiopharmaceuticals

107

View full text Add to dashboard Cite

(211)At is a promising radionuclide for α-particle therapy of cancers. Its physical characteristics make this radionuclide particularly interesting to consider when bound to cancer-targeting biomolecules for the treatment of microscopic tumors. (211)At is produced by cyclotron irradiation of (209)Bi with α-particles accelerated at ~28 MeV and can be obtained in high radionuclidic purity after isolation from the target. Its chemistry resembles iodine, but there is also a tendency to behave as a metalloid. However, the chemical behavior of astatine has not yet been clearly established, primarily due to the lack of any stable isotopes of this element, which precludes the use of conventional analytical techniques for its characterization. There are also only a limited number of research centers that have been able to produce this element in sufficient amounts to carry out extensive investigations. Despite these difficulties, chemical reactions typically used with iodine can be performed, and a number of biomolecules of interest have been labeled with (211)At. However, most of these compounds exhibit unacceptable instability in vivo due to the weakness of the astatine-biomolecule bond. Nonetheless, several compounds have shown high potential for the treatment of cancers in vitro and in several animal models, thus providing a promising basis that has allowed initiation of the first two clinical studies.

show abstract

Inorganic Astatine Chemistry: Formation of Complexes of Astatine

Cited by 35 publications

References 14 publications

Astatine Standard Redox Potentials and Speciation in Acidic Medium

Astatine Standard Redox Potentials and Speciation in Acidic Medium

Extraction of astatine-211 in diisopropylether (DIPE)

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Contact Info

Product

Resources

About

Inorganic Astatine Chemistry: Formation of Complexes of Astatine

Cited by 35 publications

References 14 publications

Astatine Standard Redox Potentials and Speciation in Acidic Medium

Astatine Standard Redox Potentials and Speciation in Acidic Medium

Extraction of astatine-211 in diisopropylether (DIPE)

Production of [211At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Contact Info

Product

Resources

About

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy